First of all, our initial raises in general are 4BB +1BB for each limper.
In the Hand there were 3 people in the pot before you, so you should've raised to 1,75$ preflop to protect against weaker hands.(Aces are the absolut best hand here, so we want to get money in the pot while still being sure to be best)

On the Flop we can't assume anyone has the flush already, the probability for this is just not that high for us to fear it. But there is a great chance that anyone has a single
and is drawing to a flush, so we need to bet a big amount to get people to pay for their draws.
To do this, an All-In on the flop is necessary and the right play in this case.

Originally posted by FlaviaMomo
I can see me making an allin on the flop with A
, but with those two maybe id rather fold... or make a cbet (1/2 pot) and if i get a call just c/f

Seriously, this would be a terrible play!
The chance of someone flopping a flush is just really low and in nearly all cases someone will have a good flushdraw but no flush. So we have to go All-In immediatly.
Of course we would prefer to have the A
, but even without our Hand is way too good to give up here!